1. Field of the Invention
The present invention relates to an electronic circuitry for a photographic camera, and more particularly to a control circuitry for controlling the operations of various circuits incorporated in the camera.
2. Description of the Prior Art
Many of recent photographic cameras are provided with various electronic circuitries and a battery for supplying power thereto. And, as functions of the camera are electronically carried out, functioning circuits such as an automatic exposure control circuit, an automatic focusing circuit, a driving circuit for a motor for winding-up and rewinding a film and a large load circuit such as an electronic flash circuit and the like are incorporated in the camera.
However, when the large load circuit and the functioning circuits are operated simultaneously, noise induced or caused by the operation of the large load circuit is erroneously input to the functioning circuits or the potential of a control signal for the operation of the functioning circuits is erroneously changed due to the drop of the power supply voltage caused by the operation of the large load circuit and there sometimes occurs misfunctioning of the circuits. For this reason, there have been disclosed various systems which inhibit the large load circuit and the functioning circuits from the simultaneous operations thereof. For instance, U.S. Pat. No. 3,917,395 teaches an electronic circuitry for a photographic camera including a switch for selectively connecting an oscillator for an electronic flashing device and the automatic exposure control circuit to a power supply device. According to this system, however, the electronic flash circuit and the automatic exposure control circuit being selectively operated, while the switch is selected for supplying the power to the electronic flash device, it is impossible to control the other functions of the camera, whereby a rapid photographic operation is difficult.